#include <iostream>

using namespace std;

int f[20] = {1, 1};

int main(){
    int n;
    cin >> n;
    for(int i = 2; i <= n; i++){
        for(int j = 0; j < i; j ++){
            f[i] += f[j] * f[i - j - 1];
        }
    }
    cout << f[n] << endl;
    return 0;
}